Method of roasting sulfurous ores.



UNITED STATES ATENT OFFICE.

ADOLF SAVELSBERG, OF AACHEN, GERMANY.

METHOD OF ROASTING SULFUROUS ORES.

Tooll whom it may concern:

Be it known that I, Anonr SAVELSBERG, a subject of tlieGerrnan Emperor, and a resident of Aachen, 131 Kaiser-Alice, have invented a new and Improved Method of Roasting Sulfurous Ores, of which the following is a full, clear, and exact description.

The present invention relates to a method of roasting sulfurous ores and consists in the ores being in the first place partly desuli'urized .by roasting the same in a converter, and destroying the structure resulting from the, sintering thus arising, which is detrimental to the final roasting process, by treatment with water, after which thismass or this mass mixed with more suliurous ore in its crude state is blown through again in the converter.

The desulfurization of sull'urous ores has been carried out in such a way that the roasting process was divided into a preliminary roasting and a final roasting, and both these processes took place in separated apparatus, the first in reverberatory furnaces with the employment of combustible material, the second in the converter. The air had to gain access to all the particles of ore in the first roasting process and a premature sintering'oi the ores had to be prevented. In order to attain ,this the ores were kept continuously in motion in the reverberatory furnace by, means of suitable stirring, whereby on the one hand the grains of ore were prevented mechanically from being baked together or were broken up, and on the other hand a constant mixing of the grains of ore was obtained, so that the oxidizing air passing over the latter came gradually into, contact with all the particles of ore. It would be of advantage even in the first roasting process to supply the oxidizing air to the ore by blowing it through the ore, instead 01' letting it act only on the .upper surface of the charge as in the'first roasting in the reverberatory furnace. The trouble and expense of stirring the mass would be thus obviated, and expensive complicated furnaces would be made superfluous, and also the first roasting process could take place in an exceedingly simple apparatus, 7;. e; in the converter, and almost without the expense of combustible mate-\ rial. It has, however, been found, that it is not possible for the firstroasting to take place in the converter in such a way that the ores remain powdery during this ing of thoreverberatory furnace by continuously stirring the ore; on the contrary sintering of the ore takes place very soon. But it has proved desirable for some kinds of ore to divide the previous process for the roasting or s'ulfurous ores in the converter into two parts namely, into a' first and into a final roasting, since such ores if l roasted in one operation retain too muchsulfur.

Now an important object of the present invention is -+t1-make possible the: division of the roasting process into two parts also with roasting in the converter by Specification of Letters Patent.

Application filed September 17.1906. Serial No. 335.918.

' tice and uneconomical.

Patented Nov. 12, 1907.

I means of blowing, in spite of the sintering taking place in the first roasting, and thereby making complicated roasting apparatus superfluous and also reducing the combustible material for the first roasting to zero. This is attained by carrying out the process in such a manner that during the first or preliminary roasting in .the converter only a superficial sintering takes place, and thereafter the sintering oi the charge, which is deleterious or harmful to the succeeding roasting, is destroyed by thoroughly moistening the sintered mass with water or other suitable liquids.

The method in accordance with the present invention is preferably'executed as follows:-The ores are mixedwith a material which possesses the property of swelling when it absorbs water, or gets it by heating, and thereby acts as a disintegrating agent, that isto say, relaxes the cohesion of the masses surrounding it. As such an addition limestone, for example, is suitable. 1n mixing sulfurous ores with limestone or the like the proportion of the alkalies to the acids may be regulated in such a way that complete scorific'ation of the mixture thus prepared does not take place during the blowing, but onlya superficial sintering and also only a partial desulfurization of the ore. The added limestone-is contained in the sintered mass partly in the form of burnt lime, CaO, and partly-as sulfate of lime, 02180,, and partly but least of all, as silicate. The mixture 'blown through in the above mentioned manner, which has a superficial sintered mass possessing the shape of the converter, still contains too much sulfur for the subsequent shalt-furnace process and must therefore be desuliurized in a second blowing process. But in this case it is necessary to pulverize the material to be calcined. Mechanical pulverization by means of a hammer and wedge, or stone breakers, or other mechanical auxiliary means has proved impracticable in prac- If, however, the sintered mass has water poured over it, theburnt lime contained in it exercises an explosiveeffect on the body when the water is soaked up, so that the sintered mass is shattered and can be brought with ease into the state suitable for a second blowing process. The above described action of the lime is assisted by sulfates which limestone or the'like may be omitted. Also the blast ingpr blowing process may be varied according-to the character in each case, sothat only part of the whole of the special swelling substance required is added in the 'first blowing, and then the remaining material is added at the iinal blowing in which case this remaining material subsequently added acts chemically on the ore mass, 0. g. as a slag forming material; or when blowing without special swelling substances. namely when the ores contain suiiicient suitable foreign constituents, so that the structure of the sintered mass which forms can be destroyed again by means of water. and only adding limestone or the like at the second blowing.

It may be pointed out that the limestone. as well as the ore at the first blowing, may be employed in fairly coarse for nrin this method of roasting, whereby; iirstly,

the costs of grinding are saved. and,'secondly, the reactions in the first blowing take place less-intensively which is very desirable; the pulverization of the limestone and of the ore necessary for the second blowing process (final roasting) then takes place in a very suitable and advantageous manner by treating with water the body first obtained in the roasting process. The first blowiiig accomplishes only a partial desuli'urization, the product being readily'disintegrated with water. It is however, not practicable to roast to a linish by a single blowing in the converter in one operation,

for the reason that the product which would become a hard'sintered mass would contain too much unroasted sulfid ore and undecomposed sullites inclosed within the roasted mass. Consequently I disintegrate after the first roasting and then roast again. i

What I claim as my invention and desire to secnrelby Letters Patent is:-

1. A method of roasting sulfurous 'ores consisting in roasting the crude ore in a converter in the presence of a substance which after being heated swells up" in contact with water, and thereby partially desulfurizing the same,

adding water to the mass thus-obtained and thereby desl'l'0 \'ing' the structure resulting from the sintering of the I same. and roasting, the mass again under the action of a blast in a converter. v

1.; A' method of roasting sulfurous ores consisting in roasting the crude ore in a converter in the presence of a substance which after being heated swells up in contact with water, and thereby partially desulfurizing the same, adding water to the mass thus obtained and thereby destroying the structure resulting from the sintering of the same, adding crude ore to said mass, and roasting the mixturc under the action of a blast in a converter.

1;. A method of roasting sulfurons ores consisting in mixing the crude ore with a substance which after being heated swells up in contact with water, roasting said mixture in in converter and thereby partially desulfurizing the same. adding water to the mass thus obtained and thereby destroying the structure resulting from the sintering of the same, and roasting the mass again under the action of a blast converter. -l. A method of roasting sulfurous ores consisting in 1 mixing the crude ore with limestone, roasting said mixture inn converter and thereby partially desulfurizing the 1 same, adding water to the mass thus obtained and thereby destroying the structure resulting from the sinterlng of the some, and roasting the mass again under the action of a blast in a converter.

3. A method, which comprises roasting snlfurous ores in a converter in the presence of a substance which after being heated disintegrates in water, dumping the charge, wetting the same, and charging the wet disintegrated mass into a converter and roasting the same under the action of the blast. I a

6. A method of roasting sulfurous ores consisting in mixing the crude ore with limestone, roasting said mixture in a converter and thereby partially desulfuriziug the same, adding water to the mass thus obtained and thereby destroying the structure resulting from the sintering of the same, disintegrating the same, inixing limestone with said disintegrated mass, and roasting the latter mixture again under the action qf a blast in a converter.

In witness whereof, I have signed my name in the presence of two subscribing witnesses.

' ADOLl SAVELSBERG.

Witnesses IIENRY QUADFLrnu, .ToHN N ssnn. 

